Just was Dyno'ed; they say I'm too lean

[Willtill]

Hi all,

As some of you know, I recently removed my cat box, and installed a cat bypass. Also loaded the 20219 tune via TuneBoy (Rocket Classic with cat bypass and aftermarket pipes), with secondaries at 100 percent. Stock silencers are still installed, as well as the stock intake.

Here at the Cancun Cantina, they had a bike day, and I was lucky enough to get American Cycle Performance to give me a free analysis of the current setup. Below are the results:



As you can see, the blue line in the below graph representing air -vs- the fuel is much more pronounced @ 2200-3200 rpm. They recommended that I needed to enrich the mixture.

From reading on Tuneboy's website, Wayne recommended that to enrich the fuel mixture; all values in the below AF table can be selected and the ratio's reduced to attain this result (richer mixture).

Link Removed

The AF table I posted below is from the 20219 tune. I am thinking about selecting all the cells in the AF table and dropping all the values by one whole number, to match what Wayne is talking about



I don't want to mess with the F1 -F3 tables. I am thinking this would be the best way overall to enrich the fuel air mixture. Thoughts?

 

[dougl]

Your second run, the red one, is not bad. The power curves in both runs are perfectly smooth. Why is there such a big difference between the first and second run run A/F? What if they had done a third run?

Your A/F is fine above 3800 rpm, so don't change the entire table. If you want to try to decrease the 14.57 values, be sure to uncheck the O2 sensor box in the tune constants.

 

[Pig9r]

Do it in the Fuel % trim table. However, you are kind of blindly throwing darts. The best way is to hook up a PCIII, do a full dyno tune on a Dynojet dyno then import the PCIII map into Tuneboy then load that tune.

 

[dougl]

Agree with Pig9r. Adjust the fuel with the fuel tables. However, At values around 14 at lower rpm, I don't think there's anything wrong. The stock Triumph 20219 is for an exhaust system which is less restrictive than the one you have.

 

[Willtill]

Hi Dougl and Brian,

Thanks for your analysis of the Dyno chart. I appreciate it. While my bike has enough power (for now ) I am just a little paranoid that it is running lean, especially after the remarks from the guy at the Dyno van I was at today.

Brian,

My fuel trim table in the 20219 tune is all zero's. I'm not sure where to begin (which way to go; positve or negative) with changing the values from zero.

I'm not sure why there was such a difference between the two runs; It did seem that the Dyno operator ran the bike much harder during the second run. Was the difference due to the motor being a lot hotter as a result of the first run?

Dougl,

Since I'm running 20219, would my engine run less lean in my current configuration; as opposed to having TOR's installed? My whole point in selecting the 20219 tune was to negate any lean conditions. Would there be a better tune for me to use in my current configuration, such as a standard Rocket 3 tune?

 

[Willtill]

I was looking at the A/F table, and between 2200-3000 RPM, at 15-20 percent throttle; looks like if I bump up that values slightly; it would take care of the lean condition.

Look at the A/F table that I posted earlier. Would that make sense, what I'm saying?

 

[dougl]

Since the TORs are less restrictive, you get more air flow, thus you would need more fuel. So the TORs tune you're using should be richer than you need, at least at the upper end. Triumph intentionally makes their tunes lean for emissions standards, but not dangerously lean.

That said, you've got A/F 13.0 above 3800 which is supposedly ideal. And you have 14.5 at 2200 rpm on the second run. I'm even skeptical about this, since it changed so much from the first run. A lot of tuners don't get the O2 sensor positioned right. I once had a dyno test which said my A/F was off scale (high). This was crap. It's really unlikely that a stock Triumph tune, especially the TOR/cat bypass tune, is going to damage your engine. I wouldn't do anything.

 

[dougl]

Like Brian said, if you want to add fuel, use the fuel trim table.

 

[Willtill]

Hi Dougl,

Thank you. I'll sleep a little better tonight, with what you said.

 

[Willtill]

This is still bugging the chit out of me.....

Please take a look at the below AF Table again for 20219 tune. I highlighted the cells that seem to directly correspond to the "lean curve" that was represented on the Dyno chart. The values seem to correlate directly to the lean mark on the graph. Would not dropping these values down to the 13's reduce the leaness, since the A/F ratio contains more fuel with the lower values?